There really are women who have horribly heavy, prolonged, painful, etc. periods, and you can feel like a slave to them if treatment doesn’t help. And like she pointed out, PMS is real and does affect many women – some every month, others only occasionally or not at all.
The problem is when people use it as a reason to keep women from doing certain jobs or holding certain positions. That’s ridiculous, because there are plenty of other health issues people deal with, including chronic Assholitis or a debilitating case of Moronicy, that aren’t considered to be disqualifying conditions.
I read once that while women have pronounced hormonal fluctuations once a month, men have ten hormone cycles a day. Sumpin’ ta think about…